The study, published in the journal Computers in Human Behavior, found that sixth-graders who went five days without exposure to technology were significantly better at reading human emotions than kids who had regular access to phones, televisions and computers.

The UCLA researchers studied two groups of sixth-graders from a Southern California public school. One group was sent to the Pali Institute, an outdoor education camp in Running Springs, Calif., where the kids had no access to electronic devices. For the other group, it was life as usual.

At the beginning and end of the five-day study period, both groups of kids were shown images of nearly 50 faces and asked to identify the feelings being modeled. Researchers found that the students who went to camp scored significantly higher when it came to reading facial emotions or other nonverbal cues than the students who continued to have access to their media devices.

"We were pleased to get an effect after five days," says Patricia Greenfield, a senior author of the study and a distinguished professor of psychology at UCLA. "We found that the kids who had been to camp without any screens but with lots of those opportunities and necessities for interacting with other people in person improved significantly more."

If the study were to be expanded, Greenfield says, she'd like to test the students at camp a third time — when they've been back at home with smartphones and tablets in their hands for five days.

"It might mean they would lose those skills if they weren't maintaining continual face-to-face interaction," she says.

A Wake-Up Call For Educators

There's a big takeaway for schools, Greenfield says.

"A lot of school systems are rushing to put iPads into the hands of students individually, and I don't think they've thought about the [social] cost," she explains. "This study should be, and we want it to be, a wake-up call to schools. They have to make sure their students are getting enough face-to-face social interaction. That might mean reducing screen time."

"Common sense tells me that if a child's laying on his or her bed and texting friends instead of getting together and saying, 'Hey, what's up,' that there's a problem there," she says. "I want people interacting ... on a common-sense level, and an experiential level. It does concern [me]."

Hogan relates the UCLA study's findings back to research on infants.

"When babies are babies, they're learning about human interaction with face-to-face time and with speaking to parents and having things they say modeled back to them," she says. "That need doesn't go away."

How Much Screen Time Is Too Much?

For decades the AAP has warned that children need to cut back on their screen time. The group's latest prescription: Entertainment "screen time" should be limited to two hours a day for children ages 3-18. And, for 2-year-olds and younger, none at all.

The sixth-graders who made up the sample in the UCLA study self-reported that they spent an average of more than four hours on a typical school day texting, watching television and playing video games.

"If used appropriately, it's wonderful," Hogan says of digital media. "We don't want to demonize media, because it's going to be a part of everybody's lives increasingly, and we have to teach children how to make good choices around it, how to limit it and how to make sure it's not going to take the place of all the other good stuff out there."

"We really need to be sure that children, and probably older people, are getting enough face-to-face interaction to be competent social beings," Greenfield says. "Our species evolved in an environment where there was only face-to face-interaction. Since we were adapted to that environment, it's likely that our skills depend on that environment. If we reduce face-to-face interaction drastically, it's not surprising that the social skills would also get reduced."

What About 'Educational Screen Time'?

Research out of the Joan Ganz Cooney Center, a nonprofit research and production institute affiliated with the Sesame Workshop, suggests that less than half the time kids between the ages of 2 and 10 spend in front of screens is spent consuming "educational" material.

The center also looked at family income as a determining factor of screen time. Lower-income families reported that their children spent more time engaging with educational screen activities than higher-income families did. Fifty-seven percent of screen time for families earning less than $25,000 was education-focused, compared with 38 percent for families earning between $50,000 to $99,000.

How To Limit Kids' Screen Time?

Of course, as media multiplies, it's increasingly difficult to manage kids' screen time. Where several decades ago, television was the only tech distraction, kids now have smartphones, tablets and laptops — not to mention electronic games.

"We need to make media a part of our lives, but in a planned, sensible way," Hogan says.

Her suggestion: Families should encourage a "healthy media diet" for their children. Parents and kids should work together to decide how much time to spend with media every day, and to make sure good choices are being made about what media to take in.